About Gryaab

Welcome to Gryaab and the Rya Wastewater Treatment Plant. Here at the plant we receive wastewater from eight municipalities in the  Gothenburg region. After the water has been treated, it’s released into the Göta Älv estuary and flows to the sea.

The short history of waste water in Gothenburg

Gothenburg has a population of 600 000 and is situated in the southwest of Sweden. Since Gothenburg was founded in 1621, the city has grown and developed into a modern industrialized city with a major port and home to industries. In a time of rapid expansion for the city in the middle of the 1800’s, sewer systems began to be built, with the aim of limiting smell and the spread of disease by transporting wastewater and rain from the city center and into the estuary. This system was expanded and developed for the next century. Gryaab was born!

Besides the implementation of the sewers, the single largest development regarding wastewater handling and treatment within Gothenburg and its surrounding municipalities was the decision to collect and treat the wastewater. This was done by creating a system of tunnels to collect the wastewater and lead it to a large centralised regional wastewater treatment plant. To this end a company owned by the municipalities, Gryaab was created.

In 1972 The Rya WWTP was commissioned which included a tunnel system of 130 km, and relatively standard wastewater treatment facility serving a population equivalent of with requirement mainly for reduction of organic material to the estuary.

50 year of waste water treatment

Plenty has happened at the plant in the last 50 years. Today the plant serves a population equivalent of 800 000 and has significantly more stringent discharge consents. The plant has been modified, rebuilt, or retrofitted several times during the last five decades and is today a fully automated plant with an innovative combination of traditional processes such as activated sludge with more modern biofilm processes and microscreens for additional particle removal.

A large proportion of the combined sewers within the city of Gothenburg and some of the municipalities still exist which means that the plant has been developed to cope with high peak flows to the plant during heavy rainfall.

Sustainable waste water treatment

Looking toward the future, the population within the region is expected to grow, new municipalities may also connect to the system and more stringent discharge consents are expected. As a result of this, a project called New Rya was initiated in 2021 to look at potential solutions to our challenges. Additional treatment processes will be ready for action in 2036.

About Gryaab